I assume you intended to create an instance of that player scene, but you haven't done that. So, right now, your
player variable is simply a string containing a path to a scene. And, since a string doesn't have a
movespd property, that causes your error.
I'd assume you're trying to do something like this:
onready var player_scene = preload("res://entities/player.tscn")
player = planer_scene.instance()
player is now an instance of the player _scene. So, assuming that scene has a script attached that provides the referenced
movespd property, that should fix your error.